Kumi Kouji (久見 幸次, くみ こうじ lit. Kumi Kouji) is the deliquent that used a love letter to lure Aren (Kumi used a pen name Kumiko) to meet with him and his gang to beat him up not knowing that Aren is stronger than them, they met their demise after being overpowered by Aren who beat them up easily.

Trivia

His real name Kumi Kouji and character profile was found in the character guidebook.[1]